I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG

A GFCI measures the common mode current flowing on the "hot" and
"neutral" conductor combination, and is designed to trip quickly when
this exceeds a small, set value (indicating that the individual currents
on the two conductors are unequal). And common mode current is just what
your signal is inducing on those wires. What you need to do is block the
common mode RF without upsetting the detection of common mode 60 Hz AC.
What I'd try is to clamp a ferrite core over the combination of black
and white wires on each side of the GFCI. A single pass through most of
the common ferrite cores should have a very low impedance at 60 Hz, so
shouldn't inhibit normal GFCI operation, but would add significant
impedance to the common mode RF. I've never had to do this, though, so
it would be interesting to hear from people who have had to deal with
this problem.

Roy Lewallen, W7EL

John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG

Thank you very much for your suggestion. Your solution is much easier than
my bypass method and can not possibly violate any wiring codes.
John, N9JG

"Roy Lewallen" wrote in message
...
A GFCI measures the common mode current flowing on the "hot" and "neutral"
conductor combination, and is designed to trip quickly when this exceeds a
small, set value (indicating that the individual currents on the two
conductors are unequal). And common mode current is just what your signal
is inducing on those wires. What you need to do is block the common mode RF
without upsetting the detection of common mode 60 Hz AC. What I'd try is to
clamp a ferrite core over the combination of black and white wires on each
side of the GFCI. A single pass through most of the common ferrite cores
should have a very low impedance at 60 Hz, so shouldn't inhibit normal GFCI
operation, but would add significant impedance to the common mode RF. I've
never had to do this, though, so it would be interesting to hear from
people who have had to deal with this problem.

Roy Lewallen, W7EL

John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire
feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the
house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on
the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG

John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on the
house exterior. None of these outlets are normally in use.

The most likely explanation is that you have large RF currents in the
power wiring of the house, due to some combination of common-mode
currents on the feedline, and/or direct coupling from the hot end of the
doublet into the house wiring in the roof.

Those RF currents will then flow to ground through the power wiring. At
the same time they will couple into the live and neutral wires, and then
flow through your GFCI in common-mode (roughly equal currents, in phase
on both wires). Since most GFCIs have poor common-mode rejection at
frequencies much higher than 60Hz, a substantial RF voltage can be
coupled through to the inputs of the IC amplifier inside the GFCI - so
it trips.

That is my best guess. To find out what's really happening, you need a
clamp-on RF current meter such as the MFJ-854 (not the MFJ-853 - it's
rubbish) or build your own from the information he
http://www.ifwtech.co.uk/g3sek/clip-on/clip-on.htm
http://www.w8ji.com/building_a_current_meter.htm

IMO this meter is the ONLY way to see and understand where the RF
currents are flowing. Then you can take steps to minimize them.

(By the way, you can almost certainly forget about an "RF ground". From
a 2nd-floor shack it's almost impossible to provide a ground path that
has a low enough impedance to shunt significant fraction of the RF
current away from the mains wiring.)


Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

Capacitors on the power wiring are the wrong answer anyway. Almost
certainly, you need series chokes. K9YC's article about ferrite chokes
and RFI is essential reading, and an article by W1HIS (although way
over-the-top for most people) is full of practical ideas:

http://audiosystemsgroup.com/RFI-Ham.pdf

http://www.yccc.org/Articles/W1HIS/C...S2006Apr06.pdf
(or http://tinyurl.com/qnzs3 )


Use the RF current meter to track down the power conductors that are
carrying the largest RF currents, and then see what some ferrite chokes
will do. Obviously the first place to try the meter will be on the
various wires coming into the breaker panel, and that should give you a
good clues about where the RF is getting in.

But almost certainly you should start applying chokes in the 2nd-floor
wiring, and especially in the shack. Keep repeating the current
measurements at the breaker panel to monitor your progress, but try to
avoid making modifications there.

As W1HIS found, another reward for cleaning up RF currents on the house
wiring is likely to be greatly reduced noise on receive.



--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Thanks for your comments and the link. A thought has just occurred to me
that perhaps I could damp out the rf energy in the unloaded wiring by
plugging a low wattage bulb (perhaps 5 watts) into one of the GFCI protected
sockets and see if that eliminates the problem.

Initially I had a small freezer in the garage plugged into one of the
sockets and some days later wondered why the freezer was no longer working.
At that time I discovered that the garage wall was also equipped with a
special non-GFCI protected socket which was installed by the house builder
specifically for a garage located freezer. After throwing out the spoiled
food and cleaning the freezer interior, I moved the freezer and plugged it
into the proper socket.

John, N9JG

"chuck" wrote in message
...
John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire
feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the
house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on
the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG



Hi John,

The quick answer is that anything that will reduce common-mode currents on
the branch wiring will be a move in the right direction. At 60 Hz, the
GFCI is supposed to trip at 5 mA. At 7 MHz, who knows?

Some experimentation may be in order: why not try ferrite beads on the
wires near the GFCI. Remember that common-mode currents may enter the GFCI
from either direction. High-quality capacitors rated for the voltages
involved would work too but seem like a less elegant solution.

If you do go with the caps, you can do a test by plugging them into the
outlets not normally in use: a quick and dirty approach that makes no
permanent change to the wiring. Be safe, of course.

Here's a link that talks a little about this:

http://www.ce-mag.com/archive/06/ARG/webb.htm
Common-Mode Signals and Radiated Emissions

73,

Chuck

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John, N9JG wrote:
Thank you very much for your suggestion. Your solution is much easier than
my bypass method and can not possibly violate any wiring codes.
John, N9JG

"Roy Lewallen" wrote in message
...
A GFCI measures the common mode current flowing on the "hot" and "neutral"
conductor combination, and is designed to trip quickly when this exceeds a
small, set value (indicating that the individual currents on the two
conductors are unequal). And common mode current is just what your signal
is inducing on those wires. What you need to do is block the common mode RF
without upsetting the detection of common mode 60 Hz AC. What I'd try is to
clamp a ferrite core over the combination of black and white wires on each
side of the GFCI. A single pass through most of the common ferrite cores
should have a very low impedance at 60 Hz, so shouldn't inhibit normal GFCI
operation, but would add significant impedance to the common mode RF. I've
never had to do this, though, so it would be interesting to hear from
people who have had to deal with this problem.

Roy Lewallen, W7EL

John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire
feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the
house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on
the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG




John,

If the GFCI is indeed a breaker, as you said, then you will not be able
to access the line side of the hot wire. That connection will be from
the back of the breaker to a bus bar in the panel. You should still be
able to apply a ferrite core to the load side. Most breaker-type GFCI
units will have connections for the black and white load wires close
together on the end of the breaker.

73,
Gene
W4SZ

John, N9JG wrote:
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG



Hi John,

The quick answer is that anything that
will reduce common-mode currents on the
branch wiring will be a move in the
right direction. At 60 Hz, the GFCI is
supposed to trip at 5 mA. At 7 MHz, who
knows?

Some experimentation may be in order:
why not try ferrite beads on the wires
near the GFCI. Remember that common-mode
currents may enter the GFCI from either
direction. High-quality capacitors rated
for the voltages involved would work too
but seem like a less elegant solution.

If you do go with the caps, you can do a
test by plugging them into the outlets
not normally in use: a quick and dirty
approach that makes no permanent change
to the wiring. Be safe, of course.

Here's a link that talks a little about
this:

http://www.ce-mag.com/archive/06/ARG/webb.htm
Common-Mode Signals and Radiated Emissions

73,

Chuck

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http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
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"John, N9JG" wrote in
et:

I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with
open-wire feed line, and elevated about 30 feet with the support for
one end attached to the house chimney. My shack is in a 2nd floor
bedroom, and the circuit breaker panel is located in the basement at
the opposite end of the house. The house has a brick exterior, and one
end of the antenna is only a few feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit
breaker, which is located in the house circuit breaker panel, moves to
the open position. None of my station equipment is attached to this
breaker; this particular breaker powers four outlets in the garage and
two outlets on the house exterior. None of these outlets are normally
in use. Is it possible (or even desirable) to install one or more
bypass capacitors inside the breaker panel, and immediately adjacent
to, the ground-fault circuit interrupter? If so, what type of
capacitor is recommended?

John, N9JG



I think GFCI refers to a breaker that operates on a small imbalance of
current on the active and neutral wires (or whatever you call them) of
the AC distribution. Typically, such things operate on quite small
current differential (30mA for standard devices in our part of the world)
and with fast operate times (~20mS). To perform this function they use
electronics to amplify the current difference from a current transformer,
and operate the breaker trip magnet. The electronics is usually powered
from the AC line. Do not overlook the potential for RF interference with
the electronics, although they should be designed for electromagnetic
compatibility, your switch may be susceptible to the levels that occur on
its AC line terminals.

Others have addressed whether the switch is responding to differential RF
currents. My guess is that it is less likely that the above, but that is
only a guess.

If that is the problem, remedial measures include replacing the switch
preferably with a different brand (though that might not fix the
problem), changing your station arrangements to reduce the RF on the AC
distribution (which could be coming from supply or load side of your
breaker), filtering on the power lines (again this may be effective if
located on the supply or load side, but you might be limited in what
measures you can employ easily on the supply side).

Owen

"John, N9JG" wrote in message
et...
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire
feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on
the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG



If you GFCI breakers are pretty old try some new ones they seem to be more
resistant to RF interference. Ive had a similar problem and new breakers did
it for me. Solve any RF-in-the-shack problems.

Jimmie

The breaker is probably as old as the house, which is about 12 years.
Replacing the breaker is the first thing I will try.

"Jimmie D" wrote in message
...

"John, N9JG" wrote in message
et...
I am using an Orion to drive my Drake L-4B, and I operate mostly on 40
meters. My antenna is a 110 feet long dipole, center-fed with open-wire
feed
line, and elevated about 30 feet with the support for one end attached to
the house chimney. My shack is in a 2nd floor bedroom, and the circuit
breaker panel is located in the basement at the opposite end of the
house.
The house has a brick exterior, and one end of the antenna is only a few
feet from the shack.

When I operate high power on 40 meters, a GFCI equipped circuit breaker,
which is located in the house circuit breaker panel, moves to the open
position. None of my station equipment is attached to this breaker; this
particular breaker powers four outlets in the garage and two outlets on
the
house exterior. None of these outlets are normally in use. Is it possible
(or even desirable) to install one or more bypass capacitors inside the
breaker panel, and immediately adjacent to, the ground-fault circuit
interrupter? If so, what type of capacitor is recommended?

John, N9JG



If you GFCI breakers are pretty old try some new ones they seem to be more
resistant to RF interference. Ive had a similar problem and new breakers
did it for me. Solve any RF-in-the-shack problems.

Jimmie